1. Field of the Invention
This invention relates to an apparatus and methods for creating visual illusion effects, and more particularly for creating stage effects in a theater setting.
2. Description of the Related Art
Persons who have been involved in attempts to create visual illusions in the live stage productions of plays or other performances have utilized numerous types of devices to create a diversity of visual illusions. Of particular interest are illusions created by visibly merging actors or objects on a stage with a motion picture film to the degree that the observer cannot distinguish between the film and the stage and cannot tell where the boundary is.
One technique which has been used involves use of a slit screen. An actor walks on the stage through a flexible slit in a screen on which a motion is being presented. This technique is difficult to make appear realistic because the audience can generally see the slit itself and understand what has actually happened even though various efforts have been made to mask the slit visually, for example, with lights. Thus, despite use of techniques to minimize the visibility of the slit, it remains visible to anyone who sees it done more than once, and there is not a seamless merger of the real object and the projected image.
Also of interest are illusions in which a performer appears to be altered or hidden from view while being actually present on the stage. The basic invisibility effect can be achieved by any half-silvered mirror room or box with neutral or regularly patterned background. An early technique known as "Pepper's Ghost" was developed in the nineteenth century and is used in certain illusions of a haunted house. This technique uses an angled piece of glass between the audience and a stage surface. A ghost figure located off-stage where it is not visible from the audience is illuminated with bright lights so that the image of the ghost figure is reflected as a transparent image off the glass. Because of the angle and position of the glass, the transparent ghostly image of the ghost figure appears to be on stage with the "real" characters. Thus, using this technique an object may appear to be more or less transparent, but it does not ever appear completely solid.
Another method of making a character present on the stage seem to disappear, termed "metempsychosis", utilizes a mirror having variations across its surface in the amount it is silvered. For example, lines are scribed in the silvering on a standard mirror, beginning with spread-out and/or thin lines and gradually increasing the thickness of the lines and/or decreasing the spacing between the scribed lines until there is an area of plain glass from which all of the silvering has been removed. The piece of variably silvered glass is placed in a grooved track at an angle across the stage. When the glass is moved back and forth in the track, a person on the stage behind the glass is visible when there is little silvering present between the person and the viewers, and is hidden when there is dense silvering present.
The illusion appliance of Hammond (U.S. Pat. No. 1,456,233) utilizes a transparent glass mounted on an inclined plane, a translucent screen having a scene on it and positioned above the glass and reflected on it, and a second translucent screen upon which a moving picture may be projected. The moving picture appears to take place on the scene reflected in the glass.
Other methods have involved partially silvered mirrors, which are typically made by spattering, or otherwise applying silver to a glass so that a portion of incident light is reflected and a portion of the light passes through the glass depending on the extent of silvering. The patent of Rogers (U.S. Pat. No. 4,805,895) is for an image forming apparatus and method where there are no image forming surfaces. A false ceiling separates a motion picture projector and rear view projection screen from the audience viewing area. A semi-transmissive reflecting member is disposed at an angle of 13.5 to 31 degrees to a vertical plane in front of the line of sight of the viewing audience.
The Rogers patent also provides a summary of three prior "Blue Room Techniques" utilizing partially silvered mirrors. In the traditional Blue Room the mirror is vertical but at a 45.degree. angle to a plane normal to the axis of a central observer's line of sight to a stage. The real object is in the wings of the theater. In Disney's Haunted Mansion Configuration (essentially the same as Pepper's Ghost discussed above), a large percentage silvered mirror is placed vertically at a 90.degree. angle to a plane normal to the axis of a central observer's line of sight to the stage. The real objects are placed either above or below the audience area. In the Sideways Blue Room, the traditional Blue Room setup is rotated 90.degree. around the axis of the central observer's line of sight.
It is therefore an object of this invention to provide an apparatus and method for providing optical illusion effects, including the illusion that an object or character on a stage has disappeared, or is in a selected position on a stage.
It is a further object of this invention to provide an apparatus and method which utilizes invisibility to achieve merger of stage and screen images through coordination of the degree of transparency of the stage object with the appearance and disappearance of screen images.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.